I order electronic parts from China through AliExpress. More often than not because they are just not available here, and sometimes just because the price difference is so big that it would just not be worth it to me for the local price…
When ordering from China, I rarely expect to actually get original parts. As sad as it is, it’s no news that chinese companies are huge in faking things and my experiences just confirm that. So everytime I get something that might be critical for a circuit – like a voltage regulator – I do some basic testing to see if it works for me. I don’t test to the exact specs because I am sure it won’t stand up to that anyway. But I expect it to be at least somewhat close enough to the original specifications so it can be used.
In this case I purchased LDO voltage regulators.
I tested them.
And they failed horribly.
This was the offer that I chose to order: “10pcs New original SPX3819M5-L-5-0/TR SPX3819M5-5.0 SOT-23” for 0.70 US$. I ordered 5 packs, so 50 pieces in total, to make it worth the price with shipping. The actual original device is supposed to deliver 5 volts with up to 500mA on an input voltage of up to 16 volts. Since I am often using up to 12 volts in my circuits, that was my basic test case: I started with 6 volts input which is higher than the minimum and hooked an LED and a resistor up to the output to have a small load of about 50mA. I also added a capacitor as suggested by the original datasheet.
It worked at first, delivering a stable 5V as expected so I slowly ramped up the voltage on the input. Everything was fine until I reached about 9 volts – little over half the supposed maximum voltage of 16 volts – when I noticed that the current regulation of my bench power supply kicked in – I had it set to 500mA just in case. After a short spike of drawing lots of current the output suddenly had almost the same voltage as the input! The voltage regulator was broken and shorted out. If this would have been a real circuit, everything behind it would be toast as well now. I tried another regulator and double checked my circuit to make sure it wasn’t just bad luck with the first one, but two more died at almost the same voltage.
So the conclusion? Will I stop buying stuff from China? Probably not since a lot of electronic parts are just not available to consumers in Europe. I already started ordering more stuff from reputable companies like Mouser or Reichelt but sometimes the price difference makes it worth to get a not-perfect-but-working part. Cases like this make the whole experience a lot less fun but luckily it costs just a few mouse clicks on AliExpress to at least get the money back. Their service, when it comes to this kind of dispute, is actually very good and the few times I needed it it’s always been solved to my satisfaction.
This seller didn’t even question my dispute but just accepted it without comment.
I will for sure go on testing parts when I get them and I will at least try to find even more stuff locally. But unfortunately a hobby like this makes it impossible to not sometimes buy from dubious chinese sellers even though it means to run into a total fake like this from time to time… But most of the time the parts I get work for me.